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NAME | SYNOPSIS | DESCRIPTION | COMMANDS | OPTIONS | INPUT FORMATS | EMPTY DISK LABEL | BACKING UP THE PARTITION TABLE | COLORS | ENVIRONMENT | NOTES | EXAMPLES | AUTHORS | SEE ALSO | REPORTING BUGS | AVAILABILITY |
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SFDISK(8) System Administration SFDISK(8)
sfdisk - display or manipulate a disk partition table
sfdisk [options] device [-N partition-number]
sfdisk [options] command
sfdisk is a script-oriented tool for partitioning any block
device. It runs in interactive mode if executed on a terminal
(stdin refers to a terminal).
Since version 2.26 sfdisk supports MBR (DOS), GPT, SUN and SGI
disk labels, but no longer provides any functionality for CHS
(Cylinder-Head-Sector) addressing. CHS has never been important
for Linux, and this addressing concept does not make any sense
for new devices.
sfdisk protects the first disk sector when create a new disk
label. The option --wipe always disables this protection. Note
that fdisk(8) and cfdisk(8) completely erase this area by
default.
sfdisk (since version 2.26) aligns the start and end of
partitions to block-device I/O limits when relative sizes are
specified, when the default values are used or when
multiplicative suffixes (e.g., MiB) are used for sizes. It is
possible that partition size will be optimized (reduced or
enlarged) due to alignment if the start offset is specified
exactly in sectors and partition size relative or by
multiplicative suffixes.
The recommended way is not to specify start offsets at all and
specify partition size in MiB, GiB (or so). In this case sfdisk
aligns all partitions to block-device I/O limits (or when I/O
limits are too small then to megabyte boundary to keep disk
layout portable). If this default behaviour is unwanted (usually
for very small partitions) then specify offsets and sizes in
sectors. In this case sfdisk entirely follows specified numbers
without any optimization.
sfdisk does not create the standard system partitions for SGI and
SUN disk labels like fdisk(8) does. It is necessary to explicitly
create all partitions including whole-disk system partitions.
sfdisk uses BLKRRPART (reread partition table) ioctl to make sure
that the device is not used by system or other tools (see also
--no-reread). It’s possible that this feature or another sfdisk
activity races with systemd-udevd(8). The recommended way how to
avoid possible collisions is to use --lock option. The exclusive
lock will cause systemd-udevd to skip the event handling on the
device.
The sfdisk prompt is only a hint for users and a displayed
partition number does not mean that the same partition table
entry will be created (if -N not specified), especially for
tables with gaps.
The commands are mutually exclusive.
[-N partition-number] device
The default sfdisk command is to read the specification for
the desired partitioning of device from standard input, and
then create a partition table according to the specification.
See below for the description of the input format. If
standard input is a terminal, then sfdisk starts an
interactive session.
If the option -N is specified, then the changes are applied
to the partition addressed by partition-number. The
unspecified fields of the partition are not modified.
Note that it’s possible to address an unused partition with
-N. For example, an MBR always contains 4 partitions, but the
number of used partitions may be smaller. In this case sfdisk
follows the default values from the partition table and does
not use built-in defaults for the unused partition given with
-N. See also --append.
-A, --activate device [partition-number...]
Switch on the bootable flag for the specified partitions and
switch off the bootable flag on all unspecified partitions.
The special placeholder '-' may be used instead of the
partition numbers to switch off the bootable flag on all
partitions.
The activation command is supported for MBR and PMBR only. If
a GPT label is detected, then sfdisk prints warning and
automatically enters PMBR.
If no partition-number is specified, then list the partitions
with an enabled flag.
--backup-pt-sectors device
Back up the current partition table sectors in binary format
and exit. See the BACKING UP THE PARTITION TABLE section.
--delete device [partition-number...]
Delete all or the specified partitions.
-d, --dump device
Dump the partitions of a device in a format that is usable as
input to sfdisk. See the BACKING UP THE PARTITION TABLE
section.
-g, --show-geometry [device...]
List the geometry of all or the specified devices. For
backward compatibility the deprecated option
--show-pt-geometry have the same meaning as this one.
-J, --json device
Dump the partitions of a device in JSON format. Note that
sfdisk is not able to use JSON as input format.
-l, --list [device...]
List the partitions of all or the specified devices. This
command can be used together with --verify.
-F, --list-free [device...]
List the free unpartitioned areas on all or the specified
devices.
--part-attrs device partition-number [attributes]
Change the GPT partition attribute bits. If attributes is not
specified, then print the current partition settings. The
attributes argument is a comma- or space-delimited list of
bits numbers or bit names. For example, the string
"RequiredPartition,50,51" sets three bits. The currently
supported attribute bits are:
Bit 0 (RequiredPartition)
If this bit is set, the partition is required for the
platform to function. The creator of the partition
indicates that deletion or modification of the contents
can result in loss of platform features or failure for
the platform to boot or operate. The system cannot
function normally if this partition is removed, and it
should be considered part of the hardware of the system.
Bit 1 (NoBlockIOProtocol)
EFI firmware should ignore the content of the partition
and not try to read from it.
Bit 2 (LegacyBIOSBootable)
The partition may be bootable by legacy BIOS firmware.
Bits 3-47
Undefined and must be zero. Reserved for expansion by
future versions of the UEFI specification.
Bits 48-63
Reserved for GUID specific use. The use of these bits
will vary depending on the partition type. For example
Microsoft uses bit 60 to indicate read-only, 61 for
shadow copy of another partition, 62 for hidden
partitions and 63 to disable automount.
--part-label device partition-number [label]
Change the GPT partition name (label). If label is not
specified, then print the current partition label.
--part-type device partition-number [type]
Change the partition type. If type is not specified, then
print the current partition type.
The type argument is hexadecimal for MBR, GUID for GPT, type
alias (e.g. "linux") or type shortcut (e.g. 'L'). For
backward compatibility the options -c and --id have the same
meaning as this one.
--part-uuid device partition-number [uuid]
Change the GPT partition UUID. If uuid is not specified, then
print the current partition UUID.
--disk-id device [id]
Change the disk identifier. If id is not specified, then
print the current identifier. The identifier is UUID for GPT
or unsigned integer for MBR.
-r, --reorder device
Renumber the partitions, ordering them by their start offset.
-s, --show-size [device...]
List the sizes of all or the specified devices in units of
1024 byte size. This command is DEPRECATED in favour of
blockdev(8).
-T, --list-types
Print all supported types for the current disk label or the
label specified by --label.
-V, --verify [device...]
Test whether the partition table and partitions seem correct.
--relocate oper device
Relocate partition table header. This command is currently
supported for GPT header only. The argument oper can be:
gpt-bak-std
Move GPT backup header to the standard location at the
end of the device.
gpt-bak-mini
Move GPT backup header behind the last partition. Note
that UEFI standard requires the backup header at the end
of the device and partitioning tools can automatically
relocate the header to follow the standard.
-a, --append
Don’t create a new partition table, but only append the
specified partitions.
Note that unused partition maybe be re-used in this case
although it is not the last partition in the partition table.
See also -N to specify entry in the partition table.
-b, --backup
Back up the current partition table sectors before starting
the partitioning. The default backup file name is
~/sfdisk-<device>-<offset>.bak; to use another name see
option -O, --backup-file. See section BACKING UP THE
PARTITION TABLE for more details.
--color[=when]
Colorize the output. The optional argument when can be auto,
never or always. If the when argument is omitted, it defaults
to auto. The colors can be disabled; for the current built-in
default see the --help output. See also the COLORS section.
-f, --force
Disable all consistency checking.
--Linux
Deprecated and ignored option. Partitioning that is
compatible with Linux (and other modern operating systems) is
the default.
--lock[=mode]
Use exclusive BSD lock for device or file it operates. The
optional argument mode can be yes, no (or 1 and 0) or
nonblock. If the mode argument is omitted, it defaults to
yes. This option overwrites environment variable
$LOCK_BLOCK_DEVICE. The default is not to use any lock at
all, but it’s recommended to avoid collisions with
systemd-udevd(8) or other tools.
-n, --no-act
Do everything except writing to the device.
--no-reread
Do not check through the re-read-partition-table ioctl
whether the device is in use.
--no-tell-kernel
Don’t tell the kernel about partition changes. This option is
recommended together with --no-reread to modify a partition
on used disk. The modified partition should not be used
(e.g., mounted).
-O, --backup-file path
Override the default backup file name. Note that the device
name and offset are always appended to the file name.
--move-data[=path]
Move data after partition relocation, for example when moving
the beginning of a partition to another place on the disk.
The size of the partition has to remain the same, the new and
old location may overlap. This option requires option -N in
order to be processed on one specific partition only.
The optional path specifies log file name. The log file
contains information about all read/write operations on the
partition data. The word "@default" as a path forces sfdisk
to use ~/sfdisk-<devname>.move for the log. The log is
optional since v2.35.
Note that this operation is risky and not atomic. Don’t
forget to backup your data!
See also --move-use-fsync.
In the example below, the first command creates a 100MiB free
area before the first partition and moves the data it
contains (e.g., a filesystem), the next command creates a new
partition from the free space (at offset 2048), and the last
command reorders partitions to match disk order (the original
sdc1 will become sdc2).
echo '+100M,' | sfdisk --move-data /dev/sdc -N 1
echo '2048,' | sfdisk /dev/sdc --append
sfdisk /dev/sdc --reorder
--move-use-fsync
Use the fsync(2) system call after each write when moving
data to a new location by --move-data.
-o, --output list
Specify which output columns to print. Use --help to get a
list of all supported columns.
The default list of columns may be extended if list is
specified in the format +list (e.g., -o +UUID).
-q, --quiet
Suppress extra info messages.
-u, --unit S
Deprecated option. Only the sector unit is supported. This
option is not supported when using the --show-size command.
-X, --label type
Specify the disk label type (e.g., dos, gpt, ...). If this
option is not given, then sfdisk defaults to the existing
label, but if there is no label on the device yet, then the
type defaults to dos. The default or the current label may be
overwritten by the "label: <name>" script header line. The
option --label does not force sfdisk to create empty disk
label (see the EMPTY DISK LABEL section below).
-Y, --label-nested type
Force editing of a nested disk label. The primary disk label
has to exist already. This option allows editing for example
a hybrid/protective MBR on devices with GPT.
-w, --wipe when
Wipe filesystem, RAID and partition-table signatures from the
device, in order to avoid possible collisions. The argument
when can be auto, never or always. When this option is not
given, the default is auto, in which case signatures are
wiped only when in interactive mode; except the old
partition-table signatures which are always wiped before
create a new partition-table if the argument when is not
never. The auto mode also does not wipe the first sector
(boot sector), it is necessary to use the always mode to wipe
this area. In all cases detected signatures are reported by
warning messages before a new partition table is created. See
also the wipefs(8) command.
-W, --wipe-partitions when
Wipe filesystem, RAID and partition-table signatures from a
newly created partition, in order to avoid possible
collisions. The argument when can be auto, never or always.
When this option is not given, the default is auto, in which
case signatures are wiped only when in interactive mode and
after confirmation by user. In all cases detected signatures
are reported by warning messages after a new partition is
created. See also wipefs(8) command.
-v, --version
Display version information and exit.
-h, --help
Display help text and exit.
sfdisk supports two input formats and generic header lines.
Header lines
The optional header lines specify generic information that apply
to the partition table. The header-line format is:
<name>: <value>
The currently recognized headers are:
unit
Specify the partitioning unit. The only supported unit is
sectors.
label
Specify the partition table type. For example dos or gpt.
label-id
Specify the partition table identifier. It should be a
hexadecimal number (with a 0x prefix) for MBR and a UUID for
GPT.
first-lba
Specify the first usable sector for GPT partitions. This
header is ignored if the script and device sector size
differ. In this case sfdisk uses label specific default.
last-lba
Specify the last usable sector for GPT partitions. This
header is ignored if the script and device sector size
differ. In this case sfdisk uses label specific default.
table-length
Specify the maximal number of GPT partitions.
grain
Specify minimal size in bytes used to calculate partitions
alignment. The default is 1MiB and it’s strongly recommended
to use the default. Do not modify this variable if you’re not
sure.
sector-size
Specify sector size. sfdisk always uses device sector size.
Since version 2.39 sfdisk recalculates sizes from dump if the
script and device sector size differ.
Note that it is only possible to use header lines before the
first partition is specified in the input.
Unnamed-fields format
start size type bootable
where each line fills one partition descriptor.
Fields are separated by whitespace, comma (recommended) or
semicolon possibly followed by whitespace; initial and trailing
whitespace is ignored. Numbers can be octal, decimal or
hexadecimal; decimal is the default. When a field is absent,
empty or specified as '-' a default value is used. But when the
-N option (change a single partition) is given, the default for
each field is its previous value.
The default value of start is the first non-assigned sector
aligned according to device I/O limits. The default start offset
for the first partition is 1 MiB. If the offset is followed by
the multiplicative suffixes (KiB, MiB, GiB, TiB, PiB, EiB, ZiB
and YiB), then the number is interpreted as offset in bytes.
Since v2.38 when the -N option (change a single partition) is
given, a '+' can be used to enlarge partition by move start of
the partition if there is a free space before the partition.
The default value of size indicates "as much as possible"; i.e.,
until the next partition or end-of-device. A numerical argument
is by default interpreted as a number of sectors, however if the
size is followed by one of the multiplicative suffixes (KiB, MiB,
GiB, TiB, PiB, EiB, ZiB and YiB) then the number is interpreted
as the size of the partition in bytes and it is then aligned
according to the device I/O limits. A '+' can be used instead of
a number to enlarge the partition as much as possible. Note '+'
is equivalent to the default behaviour for a new partition;
existing partitions will be resized as required.
The partition type is given in hex for MBR (DOS) where 0x prefix
is optional; a GUID string for GPT; a shortcut or an alias. It’s
recommended to use two letters for MBR hex codes to avoid
collision between deprecated shortcut 'E' and '0E' MBR hex code.
For backward compatibility sfdisk tries to interpret type as a
shortcut as a first possibility in partitioning scripts although
on other places (e.g. --part-type command) it tries shortcuts as
the last possibility.
Since v2.36 libfdisk supports partition type aliases as extension
to shortcuts. The alias is a simple human readable word (e.g.
"linux").
Since v2.37 libfdisk supports partition type names on input,
ignoring the case of the characters and all non-alphanumeric and
non-digit characters in the name (e.g. "Linux /usr x86" is the
same as "linux usr-x86").
Supported shortcuts and aliases:
L - alias 'linux'
Linux; means 83 for MBR and
0FC63DAF-8483-4772-8E79-3D69D8477DE4 for GPT.
S - alias 'swap'
swap area; means 82 for MBR and
0657FD6D-A4AB-43C4-84E5-0933C84B4F4F for GPT
Ex - alias 'extended'
MBR extended partition; means 05 for MBR. The original
shortcut 'E' is deprecated due to collision with 0x0E MBR
partition type.
H - alias 'home'
home partition; means 933AC7E1-2EB4-4F13-B844-0E14E2AEF915
for GPT
U - alias 'uefi'
EFI System partition, means EF for MBR and
C12A7328-F81F-11D2-BA4B-00A0C93EC93B for GPT
R - alias 'raid'
Linux RAID; means FD for MBR and
A19D880F-05FC-4D3B-A006-743F0F84911E for GPT
V - alias 'lvm'
LVM; means 8E for MBR and
E6D6D379-F507-44C2-A23C-238F2A3DF928 for GPT
The default type value is linux.
The shortcut 'X' for Linux extended partition (85) is deprecated
in favour of 'Ex'.
bootable is specified as [*|-], with as default not-bootable. The
value of this field is irrelevant for Linux - when Linux runs it
has been booted already - but it might play a role for certain
boot loaders and for other operating systems.
Named-fields format
This format is more readable, robust, extensible and allows
specifying additional information (e.g., a UUID). It is
recommended to use this format to keep your scripts more
readable.
[device :] name[=value], ...
The device field is optional. sfdisk extracts the partition
number from the device name. It allows specifying the partitions
in random order. This functionality is mostly used by --dump.
Don’t use it if you are not sure.
The value can be between quotation marks (e.g., name="This is
partition name"). The fields start= and size= support '+' and '-'
in the same way as Unnamed-fields format.
The currently supported fields are:
start=number
The first non-assigned sector aligned according to device I/O
limits. The default start offset for the first partition is 1
MiB. If the offset is followed by the multiplicative suffixes
(KiB, MiB, GiB, TiB, PiB, EiB, ZiB and YiB), then the number
is interpreted as offset in bytes.
size=number
Specify the partition size in sectors. The number may be
followed by the multiplicative suffixes (KiB, MiB, GiB, TiB,
PiB, EiB, ZiB and YiB), then it’s interpreted as size in
bytes and the size is aligned according to device I/O limits.
bootable
Mark the partition as bootable.
attrs=string
Partition attributes, usually GPT partition attribute bits.
See --part-attrs for more details about the GPT-bits string
format.
uuid=string
GPT partition UUID.
name=string
GPT partition name.
type=code
A hexadecimal number (without 0x) for an MBR partition, a
GUID for a GPT partition, a shortcut as for unnamed-fields
format or a type name (e.g. type="Linux /usr (x86)"). See
above the section about the unnamed-fields format for more
details. For backward compatibility the Id= field has the
same meaning.
sfdisk does not create partition table without partitions by
default. The lines with partitions are expected in the script by
default. The empty partition table has to be explicitly requested
by "label: <name>" script header line without any partitions
lines. For example:
echo 'label: gpt' | sfdisk /dev/sdb
creates empty GPT partition table. Note that the --append
disables this feature.
It is recommended to save the layout of your devices. sfdisk
supports two ways.
Dump in sfdisk compatible format
Use the --dump command to save a description of the device layout
to a text file. The dump format is suitable for later sfdisk
input. For example:
sfdisk --dump /dev/sda > sda.dump
This can later be restored by:
sfdisk /dev/sda < sda.dump
Note that sfdisk completely restores partition types and
partition UUIDs. This could potentially become problematic if you
duplicate the same layout to different disks, as it may result in
duplicate UUIDs within your system.
Full binary backup
If you want to do a full binary backup of all sectors where the
partition table is stored, then use the --backup-pt-sectors
command. It writes the sectors to ~/sfdisk-<device>-<offset>.bak
files. The default name of the backup file can be changed with
the --backup-file option. The backup files contain only raw data
from the device. For example:
sfdisk --backup-pt-sectors /dev/sda
The GPT header can later be restored by:
dd if=~/sfdisk-sda-0x00000200.bak of=/dev/sda
seek=$((0x00000200)) bs=1 conv=notrunc
It’s also possible to use the --backup option to create the same
backup immediately after startup for other sfdisk commands. For
example, backup partition table before deleting all partitions
from partition table:
sfdisk --backup --delete /dev/sda
The same concept of backup files is used by wipefs(8).
Note that sfdisk since version 2.26 no longer provides the -I
option to restore sectors. dd(1) provides all necessary
functionality.
The output colorization is implemented by terminal-colors.d(5)
functionality. Implicit coloring can be disabled by an empty file
/etc/terminal-colors.d/sfdisk.disable
for the sfdisk command or for all tools by
/etc/terminal-colors.d/disable
The user-specific $XDG_CONFIG_HOME/terminal-colors.d or
$HOME/.config/terminal-colors.d overrides the global setting.
Note that the output colorization may be enabled by default, and
in this case terminal-colors.d directories do not have to exist
yet.
The logical color names supported by sfdisk are:
header
The header of the output tables.
warn
The warning messages.
welcome
The welcome message.
SFDISK_DEBUG=all
enables sfdisk debug output.
LIBFDISK_DEBUG=all
enables libfdisk debug output.
LIBBLKID_DEBUG=all
enables libblkid debug output.
LIBSMARTCOLS_DEBUG=all
enables libsmartcols debug output.
LOCK_BLOCK_DEVICE=<mode>
use exclusive BSD lock. The mode is "1" or "0". See --lock
for more details.
Since version 2.26 sfdisk no longer provides the -R or --re-read
option to force the kernel to reread the partition table. Use
blockdev --rereadpt instead.
Since version 2.26 sfdisk does not provide the --DOS, --IBM,
--DOS-extended, --unhide, --show-extended, --cylinders, --heads,
--sectors, --inside-outer, --not-inside-outer options.
sfdisk --list --label-nested=mbr /dev/sda
Print protective MBR on device with GPT disk label.
echo -e ',10M,L\n,10M,L\n,+,\n' | sfdisk /dev/sdc
Create three Linux partitions, with the default start, the
size of the first two partitions is 10MiB, and the last
partition fills all available space on the device.
echo -e 'size=10M, type=L\n size=10M, type=L\n size=+\n' | sfdisk
/dev/sdc
The same as the previous example, but in named-fields format.
echo -e 'type=swap' | sfdisk -N 3 /dev/sdc
Set type of the 3rd partition to 'swap'.
sfdisk --part-type /dev/sdc 3 swap
The same as the previous example, but without script use.
sfdisk --delete /dev/sdc 2
Delete 2nd partition.
echo "+,+" | sfdisk -N 3 --move-data /dev/sdc
Enlarge 3rd partition in both directions, move start to use
free space before the partition and enlarge the size to use
all free space after to the partition, and move partition
data too.
Karel Zak <[email protected]>
The current sfdisk implementation is based on the original sfdisk
from Andries E. Brouwer.
fdisk(8), cfdisk(8), parted(8), partprobe(8), partx(8)
For bug reports, use the issue tracker at
https://github.com/util-linux/util-linux/issues.
The sfdisk command is part of the util-linux package which can be
downloaded from Linux Kernel Archive
<https://www.kernel.org/pub/linux/utils/util-linux/>. This page
is part of the util-linux (a random collection of Linux
utilities) project. Information about the project can be found at
⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have
a bug report for this manual page, send it to
[email protected]. This page was obtained from the
project's upstream Git repository
⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
2024-06-14. (At that time, the date of the most recent commit
that was found in the repository was 2024-06-10.) If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in
this COLOPHON (which is not part of the original manual page),
send a mail to [email protected]
util-linux 2.41.devel-537-e... 2024-01-28 SFDISK(8)
Pages that refer to this page: repart.d(5), cfdisk(8), fdisk(8), udevadm(8)
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